//C04:4.4:pizza.c -- 在这个pizza，使用defination const variate
#include <stdio.h>
#define PI 3.14159
int main(void)
{
    float area, circum, radius;
    printf("What is the radius of your pizza?\n");
    scanf("%f", &radius);
    area = PI * radius * radius;
    circum = 2.0 * PI * radius;
    printf("Your basic pizza parameters are as follows: \n");
    printf("circumference = %1.2f, area = %1.2f\n", circum, area);
}